package com.liuyou.duck;

public abstract class Duck {
    public abstract void display();

    public void speak() {
        System.out.println("鸭子嘎嘎嘎");
    }

    public void swim() {
        System.out.println("鸭子游泳");
    }

    public void fly() {
        System.out.println("鸭子飞");
    }

}
